Star Stars · In Columba
Phact
Phact, α Columbae, is a blue-white subgiant in Columba: the 107th brightest star in the night sky.
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- Constellation
- Columba
- Designation
- α Columbae
- Apparent magnitude
- 2.65 · 107th brightest star in the night sky
- Spectral class
- B7IV
- Distance
- 261 light-years
- Highest at midnight
- mid December
- Position (J2000)
- RA 05h 40m · Dec −34° 04′
A blue-white subgiant, around 16,000 K, like Rigel and Spica. About 35× brighter than the faintest star the eye can see. Gives off about 470 times the Sun's visible light. The light you are seeing left around 1765.
When to see it
On the night of Sun 13 Dec 2026, when it is highest around midnight, on each city’s own clock:
| From | Rises | Highest | Sets |
|---|---|---|---|
| London GMT | 22:03 | 00:10 · 4° | 02:17 |
| New York EST | 20:27 | 00:05 · 15° | 03:42 |
| Singapore GMT+8 | 19:20 | 01:15 · 55° | 07:11 |
| Sydney GMT+11 | 17:20 | 01:06 · 90° | 08:53 |
Common questions
- Can I see it from 50° north?
- Only just. At its highest it is 6° above the southern horizon, so it needs a clear, flat view that way and clean air.
- Can I see it from 35° south?
- Yes, and well placed: at its highest it passes almost overhead, 89° up, above most of the air’s haze.
- When is the best time of year to see it?
- Around mid December, when it stands opposite the Sun and is highest at midnight. It comes round about two hours earlier each month, so by mid March it is highest in the early evening, and in mid September not until the hours before dawn.
- How far away is it, and how bright?
- It is 261 light-years away, and shines at magnitude 2.65 in our sky. From that far, the Sun would be a star of magnitude 9.3: too faint for the eye, a target for binoculars.
- Naked eye, binoculars or telescope?
- The naked eye, even from a city: at magnitude 2.65 it is brighter than the faintest stars a city sky still shows, about magnitude 4.5.
Look for
Start from Arneb: Phact is 16° south of it, a fist and a half at arm’s length.
Look for
From 50° north it barely clears the horizon, at 6°; from 35° north it climbs to 21°; from the equator it climbs to 56°; from 35° south it climbs to 89°.
Science
Phact’s surface is about 16,000 K, some 10,200 K hotter than the Sun’s 5,772 K, so its light is strongest at about 180 nm, in the ultraviolet, past the violet end of what the eye can see, where the Sun’s is strongest at 500 nm. Moved to 33 light-years, the distance astronomers compare stars at, it would shine at magnitude −1.9, brighter than Sirius, the brightest star in our sky.
Did you know
Against Arneb, the brighter star the hop starts from: the two look about as bright as each other in our sky; Arneb is 2,219 light-years away and Phact 261 light-years, so side by side Arneb would give off 77 times as much light as Phact.
Science
Phact is the 96th nearest to us of the 156 stars on these pages with a measured distance. Its nearest neighbour among them in space is Canopus, about 110 light-years from it; on our sky the two are 20° apart.
Look for
The Sun passes 57° north of Phact around mid June, when it is highest at noon, in daylight: the weeks either side are its worst time of year. From 50° north it is above the horizon for about 5 hours a day, from 35° north about 8 and from 35° south about 16. It is 29° from the plane of the Milky Way.